Electrical heating unit.



F. KUHN.

ELECTRICALJIBATINQ UNIT. APPLICATION FILED MAILB, 1913.

- Patented D ec. 8,1914.

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ELECTRICAL HEATING UNIT.

Specification of Letters Patent.

Patented Dec. 8, 1914.

0 Application filed March is, 1918. Serial No. 758,874.

and has particular reference to thec0nstruc'' tion of a heating unit which is adapted for use in connection with various constructions of electrically heated devices.

The invention consists in the construction as hereinafter set forth.

In the drawings: Figure 1 is a side eleva-. tion of the unit, Fig. 2 is a perspective view of-a port on of the unit, showing the man-.

ner of engaging one of the resistor coils therewith; and Fig. 3 is a cross section of Fig. 2 showing a step in the formation of the unit.

A is a plate formed of a rigid electricallyinsulating and heat-resisting materialsuch for instance as hard asbestos board.

B are resistor coils which are mounted upon the board A by providing the latter with series of perforatiori's'C so o'sitioned as to receive the successive convo utions of the coil.

As has been stated, the material of which the board A is composed is substantially rigid, and it is also of a somewhat brittle nature so that the engagement of-the coil with the-perforations C is a diflicult operation. To avoid this difliculty, I form at the end of each series of perforations C an obliquely-arranged slot D of suificient size to receive one convolution of the coil when arranged in alinement with the series of apertures. This permits the coil to be first enga d with said slot, as shown in Fig. 3 and y then turning or twisting the coil' about its axis, its end will be threaded successively through the apertures Cuntil the entire coil is in engagement with the board. Where there are a number of the coils, such as B B, etc., arran edin parallel relation or otherwise upon the board, these may be connected in series or multiple by securing their opposite'ends to intermediate biniin posts E. These are preferably arrange upon the board intermediate ad acent series 0 perforations, and not only electrically connect the coils but mechanically hold them from displacement. To stren hen the structure, the edges of the boar are preferably bound with metallic reinforcing strips F which may be of U-shaped section embracing the edges of the plates.

The unit as formed may be inserted in any suitable construction of electrica ly heated devices, and when connected in circuit heat will be developed in all of the coils and radiated from opposite sides of the plate.

What I claim as my invention is:

, An electrical'heating unit, comprising a flat board or plate of rigid electrically-insulating and heat-resistingmaterial, havin a series of perforations'therein positioned to engage thev successive convolutions of a resistor coil, and a slot adjacent the end of and in alinement with the series of perfo rations, of a size to receive the first convolution of the coil to permit of threading the same through said series of perforations.

In testimon whereof I affix my signature in presence 0 two witnesses.

v FRANK KUHN. Witnesses:

Janus P. BARRY, DELBERT CoLuNs. 

